Dielectric (or insulating) fluid compositions used in electrical distribution and power equipment act as an electrical insulating medium, i.e., exhibit dielectric strength, and they transport generated heat away from the equipment, i.e., act as a cooling medium. When used in a transformer, for example, dielectric fluids transport heat from the windings and core of the transformer or connected circuits to cooling surfaces.
Liquid filled electrical apparatus used in certain climates may require a dielectric fluid composition that maintains its electrical and physical properties, particularly pourability, for extended periods at low temperatures. This pourability requirement has limited the range of applications for vegetable oil based dielectric fluid compositions, which typically have pour points above about −10° C.